EVALUATION OF A COUPLED MASS TRANSPORT-BIOFILM PROCESS MODEL USING DISSOLVED-OXYGEN MICROSENSORS

A 2-dimensional model has been developed which couples hydrodynamics, solute transport and reaction in a steady state biofilm system of irre gular geometry under laminar flow. Biofilm thickness is initially spec ified over the domain and remains constant during the simulations. The Navier-Stokes equations are coupled with advection-diffusion-reaction equations describing oxygen transport and solved using finite differe nces. This model facilitates computational investigation of fluid velo city and solute concentration distributions in proximity to the fluid- biofilm interface. Model evaluation has been carried out using dissolv ed oxygen profiles measured by microsensors in a rectangular open chan nel with a 300 mu m (approximate) artificial biofilm composed of algin ate gel with an 8x10(10) cells/ml concentration of Ps. aeruginosa cell s. Significant variability in dissolved oxygen profile shape was obser ved at three locations on the artificial biofilm. Model simulations of these experiments facilitated a direct comparison between observed an d computed values of dissolved oxygen concentration in the vicinity of the fluid-biofilm interface. Simulated profiles agreed closely with m easured profiles at all three locations.